math.5

<B>Digital的Unix操作系统VAX 4.2源码</B>

.TH math 5 RISC
.SH Name
math \- math functions and constants
.SH Syntax
.B #include <math.h>
.SH Description
This file contains declarations of all the functions in the
Math Library (described in Section 3m),
as well as various functions in the C Library (Section 3c)
that return floating-point values.
.P
It defines the structure and constants used by the
.MS matherr 3m
error-handling mechanisms, including the following constant used as an
error-return value:
.P
.TP 15
.SM
HUGE
The maximum value of a single-precision floating-point number.
.PP
The following mathematical constants are defined for user convenience:
.P
.TP 15
.SM
M_E
The base of natural logarithms
.RI ( e ).
.TP
.SM
M_LOG2E
The base-2 logarithm of
.IR e .
.TP
.SM
M_LOG10E
The base-10 logarithm of
.IR e .
.TP 
.SM
M_LN2
The natural logarithm of 2.
.TP 
.SM
M_LN10
The natural logarithm of 10.
.TP 
.SM
M_PI
\(*p, the ratio of the circumference of a circle to its diameter.
.TP 
.SM
M_PI_2
\(*p/2.
.TP 
.SM
M_PI_4
\(*p/4.
.TP 
.SM
M_1_PI
1/\(*p.
.TP 
.SM
M_2_PI
2/\(*p.
.TP 
.SM
M_2_SQRTPI
2/\(sr\(*p.
.TP 
.SM
M_SQRT2
The positive square root of 2.
.TP 
.SM
M_SQRT1_2
The positive square root of 1/2.
.PP
For the definitions of various machine-dependent constants,
see the description of the
.I <values.h>
header file.
.SH See Also
intro(3), values(5)